Halyomorpha halys (Stal, 1855) Heteroptera

Murvanidze, Maka, B, Greg Krawczyk, B, Nino Inasaridze, B, Lika Dekanoidze, B, Natia Samsonadze, B, Mariam Macharashvili, B, Sopho Khutsishvili & B, Salome Shengelaia, 2018, Preliminary data on the biology of brown marmorated stink bug Halyomorpha halys (Hemiptera, Pentatomidae) in Georgia, Turkish Journal of Zoology 42 (6), pp. 617-624 : 619-622

3.1. Phenology of H. halys in hazelnut orchards

The first BMSB adults in both orchards were observed by 20 May. Only BMSB adults were captured on sticky traps until 8 July. The second instar BMSB nymphs were first captured on 8 July. After the first capture of nymphs, the immature stages became the most abundant part of the BMSB population observed in traps. At the end of July and throughout August all BMSB instars and adults were observed at the same time. In September, the numbers of nymphal stages started to decrease, and by the end of September, only adults and fifth instar nymphs were observed. In October, the number of BMSB individuals found on sticky traps decreased significantly, and by the end of the month, only two adults were found in the first orchard near the household area ( Table 2; Figures 3A and 3B ). Comparison of numbers of observed BMSB adults and nymphs present in both orchards utilizing all traps and all observation dates shows significant differences between numbers of adults (df = 1, F = 10.83, P <0.05) and 2nd and 3rd instar nymphs (df = 1, F = 25.28, P <0.05), but no significant differences were observed between the 4th and 5th instar nymphs (df = 1, F = 1.55, P> 0.05) .

3.2. Effect of temperature on biology of H. halys

The accumulation of degree days using the lower threshold of 13.9 °C was calculated starting from 6 May, the first Means within a column followed by the same letters are not significantly different (ANOVA, Fisher’s LSD test, P> 0.05, data for analyses transformed using square root transformation).

day the traps were placed in orchards. Adults from the overwintering BMSB population started to appear in orchards when average daily temperature was at or above 13–15 °C (31.25 DD 13.9). The second instar nymphs on sticky traps were first found when the temperature reached above 23°C at DD accumulation of 359.45 DD 13.9. All instar nymphs and BMSB adults were simultaneously present in traps as long as the average temperature was above 23–26 °C (DD accumulation 896–1061 DD 13.9). At about 1200 DD 13.9 only BMSB adults and fifth instar nymphs were found in traps. After the DD accumulation reached 1266 DD 13.9 only individual BMSB adults were still observed on traps ( Figure 4 ).

3.3. Distribution of BMSB individuals in orchards

The average weekly captures of BMSB adults and nymphs per trap were similar in both evaluated orchards (P> 0.05), suggesting relatively uniform distribution of BMSB adults and nymphs within both orchards ( Tables 3 and 4).

In Orchard A no differences were observed in the distribution pattern of stink bug stages in traps located close to the house. Cumulative numbers of nymphs were higher than numbers of adults, with the exception of trap number 5, which was located on the pear tree in front of the house and recorded the highest number of adults. A low cumulative number of both adults and nymphs was recorded from trap number 6, which was placed on the fig tree in the back yard ( Figure 1 ).

In Orchard B the number of adults and nymphs was always higher around the perimeter (trap numbers 11–23) than inside the orchard (trap numbers 24–31), but the Means within a column followed by the same letters are not significantly different (ANOVA, Fisher’s LSD test, P> 0.05, data for analyses transformed using square root transformation).

Means within a column followed by the same letters are not significantly different (ANOVA, Fisher’s LSD test, P> 0.05, data for analyses transformed using square root transformation). highest numbers were recorded on traps located adjacent to wild vegetation (trap numbers 11,12,13, and 14 and trap numbers 18,19, and 20) ( Figure 2 ).

Distribution of adults and 2nd and 3rd instar nymphs significantly differed among trap locations (df = 4, P <0.05, F = 3.4 for adults and F = 7.41 for 2nd and 3rd instars). For the 4th and 5th instars the differences were not significant (df = 4, F = 1.87, P> 0.05) ( Table 5).

Figures

Figure 1. Placement of sticky traps in Orchard A and cumulative number of individuals of H. halys on each trap.

Figure 2. Placement of sticky traps in Orchard B and cumulative number of individuals of H. halys on each trap.

Figure 3. The dynamics of the various stages of H. halys in A) Orchard A and B) Orchard B, Samegrelo, Georgia, 2017.

Figure 4. Degree days (DD 13.9) accumulation data for H. halys during the observation period. Solid lines indicate Orchard A, dashed lines Orchard B. BMSB traps were placed in Orchard A on 6 May 2017 and on 20 May 2017 in Orchard B.